月份：2016年7月

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.Iterator;

import javax.imageio.ImageIO;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;

public class test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String qrcode;
		try {
			//java的urldecode会指定编码,需要设置为iso-8859-1,这样输出的才是二进制
			qrcode = URLDecoder
					.decode("%89PNG%0D%0Axxxxxx",
							"ISO-8859-1");
			
			//以下为二进制内容输出为图片,不可以直接用普通方式输出图片,会导致文件头加了些东西,导致图片破坏

			ByteArrayInputStream bis = new ByteArrayInputStream(
					qrcode.getBytes());
			Iterator<?> readers = ImageIO.getImageReadersByFormatName("png");
			// ImageIO is a class containing static convenience methods for
			// locating ImageReaders
			// and ImageWriters, and performing simple encoding and decoding.

			ImageReader reader = (ImageReader) readers.next();
			Object source = bis; // File or InputStream, it seems file is OK

			ImageInputStream iis = ImageIO.createImageInputStream(source);
			// Returns an ImageInputStream that will take its input from the
			// given Object

			reader.setInput(iis, true);
			ImageReadParam param = reader.getDefaultReadParam();

			Image image = reader.read(0, param);
			// got an image file

			BufferedImage bufferedImage = new BufferedImage(
					image.getWidth(null), image.getHeight(null),
					BufferedImage.TYPE_INT_RGB);
			// bufferedImage is the RenderedImage to be written
			Graphics2D g2 = bufferedImage.createGraphics();
			g2.drawImage(image, null, null);
			File imageFile = new File("d://test.png");
			ImageIO.write(bufferedImage, "png", imageFile);
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

}